Name:
1
Properties of Atoms and Introduction to the Periodic Table – Notes
Structure of the Atom
• ___________________ are abbreviated in scientific shorthand – first
letter or two of element’s name
• ____________________– smallest piece of matter that still has the
properties of the element
Atoms
• ____________________
• ____________________
• ____________________
• ____________________
____________________
have electrical charge of _____
do not have an electrical charge
have electrical charge of _____
and ____________________ are in the
of an atom; electrons surround the nucleus
____________________ and ____________________ are made up of smaller
particles called ____________________
• Quarks are studied by ____________________ accelerated charged
particles with protons, which leave tracks in a bubble chamber
• ____________________quarks are known to exist; the sixth is called the
____________________ quark
____________________
• Said all matter consisted of four elements:
• ____________________
• ____________________
• ____________________
• ____________________
____________________ (Greek) 400BC was first to propose an
____________________ Theory
• Believed all matter was composed of small indivisible & indestructible
particles he called atoms, from Greek word atomos.
John ____________________ (early 1800’s) – atomic theory based on
experimentation
• All ____________________ are composed of ____________________
• Atoms of the same element are ____________________, atoms of
different elements are ____________________
• Atoms of different elements can join together in single whole number ratios
to form ____________________
• Chemical reactions occur when atoms are ____________________,
____________________ or ____________________
2
J.J. ____________________ (English, 1897)
• Discovered ____________________using a cathode ray tube.
• Sealed tube with vacuum inside and electrodes on each end. When
connected to electric current, a beam traveled from cathode to
anode. He called the beam “cathode rays.” They were
____________________.
• Proposed “______________________________” model of the atom.
• Was a field of ____________________ distributed positive and
negative charge.
In 1911, ________________________________________interpreted these
results and suggested a new model for the atom. He said that Thomson's model
could not be right. The positive charge must be
, otherwise the heavy alpha particles fired at foil could never be
repelled back towards their source. On this model, the electrons orbited around
the dense ____________________ (center of the atom).
____________________ (early 1900’s)
The next important development came in 1914 when Danish physicist Niels Bohr
revised the model again. It had been known for some time that the
____________________given out when atoms were heated always had specific
amounts of ____________________, but no one had been able to explain this.
Bohr suggested that the electrons must be
(or shells). The nucleus is the center of an atom,
containing protons and neutrons. The energy must be given out when 'excited'
electrons fall from a high energy level to a low one.
Scientists use scaled-up ____________________ to represent atoms.
• Early models of atoms used a solid ____________________.
• Current ________________________________________model
shows electrons traveling in specific energy levels around a nucleus of
protons and neutrons
Masses of Atoms
____________________– composed mostly of the protons and neutrons in the
nucleus
• Unit of measurement for atomic particles is ____________________
____________________ (amu) which is one-twelfth the mass of a carbon
atom containing six protons and six neutrons.
•
•
____________________– the number of ____________________ in an
atom; number of protons also ____________________ the element
The sum of the number of protons and neutrons in the nucleus of an atom is the
____________________.
3
Element
H
O
K
I
Pb
Atomic #
1
Mass #
16
Protons
Neutrons
0
Electrons
8
19
20
127
53
82
125
•
____________________ – atoms of the same element with different numbers
of neutrons
• Different isotopes have different ____________________
• Numbers of ____________________ is equal to mass number minus
atomic number
• Name of ____________________followed by mass number identifies
the isotope
•
________________________________________is the weighted-average
mass of an element’s isotopes
Average atomic mass is closest to its most ____________________ isotope
•
The Periodic Table
• Elements are organized in the ______________________________by
increasing atomic number.
• In the late 1800’s, Dmitri ____________________ devised the
first periodic table based on _________________________.
• In 1913, Henry Moseley arranged the elements by
_________________________rather than atomic mass.
•
•
•
•
•
Vertical columns in the periodic table are ____________________ of
elements with similar ____________________.
• Elements in the same group have the same number of
____________________ in their ____________________ energy
level
Each of the seven energy levels can have a ____________________
number of ____________________.
• Energy level one can contain at most ____________________
electrons
• Energy level two can contain at most ____________________
electrons
Rows in the Periodic Table are called ____________________
Each row in the periodic table ends when an outer energy level is
____________________
________________________________________use the element symbol
and dots to represent outer energy level electrons.
4
Molecular Formula
•
Electron Dot Diagram
Structural Formula
____________________ – horizontal rows of elements that contain
increasing numbers of protons and electrons.
• Elements are classified as
• Elements are ____________________ in laboratories all over the
world
Electromagnetic Radiation (Light) as a Key to Understanding Electron Paths
• Early scientists discovered that
________________________________________ (light) is given off by
atoms of an element when they have been excited by some form of
____________________. Furthermore, atoms of different elements give
off different ____________________ of light when they are excited.
Spectral Analysis of Emitted Light from Excited Atoms
• When the emitted light from excited atoms was passed through a prism, a
curious spectrum of discrete
________________________________________, separate energies was
observed rather than a continuous spectrum of ROY G BIV.
• Furthermore, different ____________________ show totally different
line spectra.
• In fact, line spectra are used to ____________________the presence of
different ____________________
Interpretation of Atomic Spectra
• The line spectrum must be related to ____________________ transitions
in the atom.
• ____________________= atom gaining energy
• ____________________ = atom releasing energy
• Since all samples of an element give the exact same pattern of lines, every
atom of that element must have only certain, identical
____________________
• The energy of an atom is ____________________ – limited to discrete
values
• If the atom could have all possible energies, then the result would be
a ____________________ spectrum instead of lines
5
Interpretation of Atomic Line Spectra in terms of Electron Paths
• ____________________ may be thought of as traveling in concentric
shells or energy levels about the nucleus.
• The ____________________ of the shells increase as one proceeds
____________________ from the nucleus.
• When an atom ____________________ energy, electrons are promoted
from an inner, ____________________ energy, shell to an outer,
____________________ energy shell.
• Conversely, when an excited atom ____________________ energy,
electrons drop down from an excited ____________________higher
energy shells to an ____________________ lower energy shells
Read pages 106 – 127 in your book, and answer the following questions on the back:
1. Characterize the size of an atom.
2. What are the charges and relative masses of the three main subatomic
particles?
3. Describe Thomson’s, Millikan’s, and Rutherford’s contributions to the atomic
theory. Include their experiments.
4. How many Protons and electrons are in each of the following atoms:
a. Flourine
b. Aluminm
c. Calcium
5. How many neutrons are in each atom?
a. 168O
c. 3216S
b. 10847Ag
d. 8035Br
6. Three isotopes of oxygen are oxygen-16, oxygen-17 and oxygen-18. Write
the complete symbol for each, including the atomic number and mass number.
How is the mass number shown on the Periodic Table determined?
7. Why are the atomic masses not whole numbers?
8. How does the atomic number of an element identify the element?
9. How can atomic number and mass number be used to find the numbers of
protons, neutrons and electrons?
10. What criteria did Mendeleev use to construct his periodic table of the
elements? How did Moseley arrange the elements? Which is used today?
11. Identify each element as a metal, metalloid or nonmetal:
a. Gold
d. Sulfur
b. Silicon
e. Barium
c. Manganese
12. Name two elements that have properties similar to those of the element
calcium.
13. What are the properties of:
a. Metals
b. Non-metals
c. Metalloids